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Issues concerning water security plague agricultural, residential, and industrial sectors worldwide, despite advances in the understanding of biophysical water system processes.Proposed solutions to water challenges have been inadequate because they do not account for the dual role of humans as both contributing to and subsequently adapting to problems. This reality has motivated researchers to consider human decision-making and activities as endogenous to water system dynamics Vogel et al., 2015). Sivapalan et al. (2012) introduced the concept of socio-hydrology as a "new science of people and water" to meet this challenge. Socio-hydrology aims to broaden the study of water cycle dynamics with explicit consideration of social processes, similar to the field of ecohydrology, which incorporates ecological processes into the study of water cycling. This poses difficulties. Unlike ecohydrology, which involves a synthesis of two natural science disciplines, socio-hydrology involves incorporation of social processes, which many consider fundamentally different from processes tackled traditionally by natural scientists and engineers. Rittell and Webber (1973) define "wicked problems" as problems with unknown or indeterminate scope and scale, and for which there may be no definitive formulation or optimal solution -specifically problems of social policy and planning. It is possible to conceptualize socio-hydrology as a science that wrestles with wicked problems. Sociohydrology does not possess a precise set of principles or testable hypotheses characteristic of physical sciences, but advocates a holistic approach to examining water system challenges through inclusion of social processes (Lane, 2014;Troy et al., 2015; van der Zaag et al., This article is protected by copyright. All rights reserved. 2014). It is therefore challenging to unambiguously articulate socio-hydrology's guiding questions and methods, reconcile preferred and available data types, and define what modeling and prediction mean to this new field. However, far from being a deterrent, this wickedness is precisely what attracts and motivates the first generation of young researchers specializing in socio-hydrology -the doctoral student authors of this paper.Student ambitions are practical: socio-hydrology is both necessary and inevitable.Researchers increasingly acknowledge the importance of incorporating social processes into the study of water resources (Montanari et al., 2015;Rajaram et al., 2015). In the original account of wicked problems, Churchman (1967) states that the decision to wrestle with the whole rather than part of a problem is fundamentally a moral decision. Students have witnessed the rise of sustainability research in the water, climate, and environmental sciences, along with the shortcomings of that research in connecting with human-decision-making, management and policy. Tackling the whole of the problem, despite its challenges, is the most appropriate way to acknowledge and address the needs of the communities we claim to serve...

Abstract. Socio-hydrology describes the interaction between the socio-economy and water. Recent models analyze the interplay of community risk-coping culture, flooding damage and economic growth (Di Baldassarre et al., 2013;Viglione et al., 2014). These models descriptively explain the feedbacks between socio-economic development and natural disasters like floods. Contrary to these descriptive models, our approach develops an optimization model, where the intertemporal decision of an economic agent interacts with the hydrological system. In order to build this first economic growth model describing the interaction between the consumption and investment decisions of an economic agent and the occurrence of flooding events, we transform an existing descriptive stochastic model into an optimal deterministic model. The intermediate step is to formulate and simulate a descriptive deterministic model. We develop a periodic water function to approximate the former discrete stochastic time series of rainfall events.Due to the non-autonomous exogenous periodic rainfall function the long-term path of consumption and investment will be periodic.